EP0310396B1 - Planar inductor - Google Patents
Planar inductor Download PDFInfo
- Publication number
- EP0310396B1 EP0310396B1 EP88309056A EP88309056A EP0310396B1 EP 0310396 B1 EP0310396 B1 EP 0310396B1 EP 88309056 A EP88309056 A EP 88309056A EP 88309056 A EP88309056 A EP 88309056A EP 0310396 B1 EP0310396 B1 EP 0310396B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- ferromagnetic
- planar inductor
- planar
- inductance
- thickness
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000005294 ferromagnetic effect Effects 0.000 claims description 131
- 239000004020 conductor Substances 0.000 claims description 64
- 229910001004 magnetic alloy Inorganic materials 0.000 claims description 2
- 230000005291 magnetic effect Effects 0.000 description 38
- 230000000052 comparative effect Effects 0.000 description 33
- 230000004907 flux Effects 0.000 description 23
- 229910000808 amorphous metal alloy Inorganic materials 0.000 description 22
- 239000000126 substance Substances 0.000 description 19
- 229920001721 polyimide Polymers 0.000 description 11
- 238000010276 construction Methods 0.000 description 8
- 230000035699 permeability Effects 0.000 description 8
- 230000005292 diamagnetic effect Effects 0.000 description 7
- 238000005530 etching Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000005096 rolling process Methods 0.000 description 6
- 239000010949 copper Substances 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 239000011889 copper foil Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000011888 foil Substances 0.000 description 4
- 230000002093 peripheral effect Effects 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000007767 bonding agent Substances 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229920000515 polycarbonate Polymers 0.000 description 2
- 239000004417 polycarbonate Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000002500 effect on skin Effects 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Substances [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 1
- -1 platinum metals Chemical class 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F17/0006—Printed inductances
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F5/00—Coils
Description
- The present invenion relates to a planar inductor. Planar inductors having a spiral coil configuration are known from IEEE Transactions on Magnetics, Vol.MAG-15, No.6, November 1979, 1803-1805. It is known to form such spiral coils on top of an amorphous magnetic thin film substrate as disclosed in JP-A-58 14512. A pair of magnetic layers may be used to sandwich a planar spiral coil, as shown in IEEE Transactions on Magnetics, Vol. MAG-20, No. 5,September 1984, 1804-1806. Another known planar inductor structure is disclosed in US-A-4 494 100.
- A typical known arrangement of planar inductors in which two
spiral conductor coils 1a and 1b are sandwiched betweenferromagnetic ribbons insulating layers conductor coils 1a and 1b, respectively, correspond to the respective center lines ofcoils 1a and 1b shown in the sectional view of Fig. 1B. Insulatinglayers Coils 1a and 1b are connected electrically to each other via throughhole 4, and form an inductor betweenterminals - If a current is applied to
spiral conductor coils 1a and 1b of the planar inductor, however,magnetic fluxes hole 4, as shown in Fig. 2. As a result,gap portions 7a and 7b, where magnetic flux density is very low, exist at two positions near the central and outer peripheral portions of each conductor coil. Accordingly, the inductance is inevitably reduced. In this case, an intensive magnetic field is generated at central gap portion 7a byconductor coils 1a and 1b, while there is hardly any magnetic field atperipheral gap portion 7b. Thus, the reduction of the inductance is much greater at the peripheral portion than at the central portion. -
Spiral conductor coils 1a and 1b, insulatinglayers ferromagnetic ribbons layers - If magnetostriction of
ferromagnetic ribbons insulating layers ferromagnetic ribbons - In a magnetic circuit of this planar inductor, if
ferromagnetic ribbons - Meanwhile, the planar inductor may be applied to an output-side choke coil of a DC-DC converter or the like. In this case, a high-frequency current superposed with a DC current flows through the planar inductor. Therefore, the inductor requires a good DC superposition characteristic.
- The conventional planar inductors have not, however, a very good DC superposition characteristic. If this characteristic of the inductor is poor, the inductance lowers, so that the control becomes difficult. Accordingly, the efficiency of the DC-DC convertor lowers. Thus, it is not appropriate to apply the plane inductor directly to the DC-DC convertor and the like.
- Here, it can be noted that a planar inductor having a planar or hoop-shaped coil is described in IEEE Trans. Mag. MAG-20 (1984) 1804-1806. Another thin-film inductor is described in IEEE Trans. Mag. MAG-15 (1979) 1803-1805. Stacking of uni-directional planar coils is disclosed in US-A-4 494 100.
- An object of the present invention is to provide a planar inductor in which inductance is prevented from lowering as its components are bonded together, so that the inductance value per unit volume is increased.
- Another object of the invention is to provide a planar inductor enjoying a small thickness and a higher inductor value per unit volume.
- Still another object of the invention is to provide a planar inductor having a good DC superposition characteristic.
- Thus the present invention provides a planar inductor comprising spiral conductor coil means sandwiched between ferromagnetic layers with insulating layers interposed therebetween, wherein each said ferromagnetic layer includes a plurality of ferromagnetic sheets each having a thickness of 100 »m or less.
- The invention also extends to a DC-DC converter comprising a planar inductor as defined in the preceding paragraph.
- Preferably, the ferromagnetic layers are formed of an amorphous magnetic alloy.
- Preferably, furthermore, the average thickness of each ferromagnetic layer ranges from 4 to 20 »m.
- Also, the ferromagnetic layers should preferably be formed of a ribbon- or film-shaped high-permeability amorphous alloy which has recently started to attract public attention. In particular, the ferromagnetic layers should have a composition given by
where M is at least one of elements selected from the group including Ti, V, Cr, Cu, Zr, Ni, Nb, Mo, Hf, Ta, W, and platinum metals, and a b, x, and y are values within ranges given by
respectively. - In the above structural formula, Fe is an element for adjusting the magnetostriction to 0, and M is an element used to improve the thermal stability of the permeability. Since the thermal stability can be improved by setting value b within the range from 0.3 to 0.7, x may be 0. Value x is restricted within the
range 0 ≦ x ≦ 0.08 because the Curie temperature is too low to be practical if x exceeds 0.08. Si and B are elements essential to noncrystallization. Value y is restricted within therange 15 ≦ y ≦ 35 because the thermal stability is too poor if y is less than 15, and because the Curie temperature is too low to be practical if y exceeds 35. Mixture ratio b between Si and B is restricted within 0.3 ≦ b ≦ 0.7 because the thermal stability of the magnetic characteristic is particularly good in that case. - According to the planar inductor constructed in this manner, the path of magnetic flux is allowed to exit only in a gap portion in the center of the spiral conductor coil means, so that the inductance per unit volume can be increased, and the inductance of the whole planar inductor can be prevented from lowering.
- By adjusting the absolute value of magnetostriction of each ferromagnetic layer to 1 × 10⁻⁶ or less, moreover, the inductance can be prevented from lowering due to stress or the like which may be produced when the components of the planar inductor are bonded together.
- By restricting the average thickness of each ferromagnetic within the range from 4 to 20 »m, furthermore, the inductance value per unit volume (L/V) can be prevented from being reduced. If the thickness of the ferromagnetic layer is less than 4 »m, the layer cannot enjoy a sectional area large enough for the passage of all the magnetic flux which is produced as the currents flow through the spiral conductor coils. Thus, leakage flux increases, so that the inductance lowers considerably, and therefore, inductance value L/V per unit volume is reduced. If the thickness of the ferromagnetic layer exceeds 20 »m, on the other hand, the sectional area of the layer in a magnetic circuit becomes large enough to allow the passage of all the magnetic flux produced in the aforesaid manner. Thus, the magnetic resistance is reduced, so that the leakage flux lessens, and the inductance increases. Since the volume of the planar inductor also increases, however, value L/V is rather reduced.
- In another arrangement there is provided a planar inductor which has spiral conductor coil means sandwiched between ferromagnetic layers with insulating layers interposed therebetween, wherein a ferromagnetic substance is disposed flush with and/or in the central portion of the spiral conductor coil means, and in a region surrounding the outer periphery of the spiral conductor coil means. Preferably the ferromagnetic substance is at least partially in contact with the ferromagnetic layers.
- Preferably, the ferromagnetic substance consists essentially of a compact of ferromagnet powder or a composite including ferromagnetic powder.
- According to the planar inductor constructed in this manner, the magnetic resistance is reduced at the central and peripheral portions of the spiral conductor coil means, so that the inductance per unit volume can be increased, and the inductance of the whole planar inductor can be prevented from lowering.
- Each spiral conductor coil means of the planar inductor is generally composed of a two-layer spiral conductor coil assembly in which spiral coils on either side of each insulating layer are connected via a through hole. Unless there is a hindrance to the removal of terminals, the spiral conductor coil means may be composed of only one spiral coil.
- Preferably, the average thickness of each ferromagnetic layer ranges from 4 to 20 »m. Moreover, the ratio (t/l) of the thickness (t) of the ferromagnetic layer to the side length (l) thereof is preferably 1 × 10⁻³ or more.
- In general, laminate planar inductors may be classified into two types. According to type I, a plurality of planar inductors, each having a construction such that spiral conductor coil means is sandwiched between ferromagnetic layers with insulating layers interposed between them, are stacked in layers. type II is constructed so that a plurality of spiral conductor coil means are stacked with insulating layers between them, and the laminated structure is sandwiched between ferromagnetic layers with insulating layers interposed between them. In type I, two insulating layers and two ferromagnetic layers exist between each two adjacent conductor coil means. In type II, on the other hand, only the insulating layer exists between each two adjacent coil means.
- As a result of an earnest investigation by the inventors hereof, it was found that the ferromagnetic layers, existing between the adjacent spiral conductor coil means, as in the case of type I, are hardly conducive to the increase of the inductance of the laminate planar inductors. It was also indicated that substantially the same inductance value for type I can be obtained even though only the insulating layer exists between each two adjacent spiral conductor coil means, without being accompanied by the ferromagnetic layers, as in the case of type II. Therefore, the planar inductor according to the present invention (type II) is generally thinner than the planar inductor of type I, and has substantially same general inductance value as type I. Thus, the inductance value per unit volume is greater.
- According to the planar inductor of this type, moreover, reduction of the inductance value per unit volume (L/V) can be prevented by restricting the average thickness of each ferromagnetic layer within the range from 4 to 20 »m. If the thickness of the ferromagnetic layer is less than 4 »m, the layer cannot enjoy a sectional area large enough for the passage of all the magnetic flux which is produced as the currents flow through the spiral conductor coils. Thus, leakage flux increases, so that the inductance lowers considerably, and inductance value L/V per unit volume is reduced. If the thickness of the ferromagnetic layer exceeds 20 »m, on the other hand, the sectional area of the layer in the magnetic circuit becomes large enough to allow the passage of all the magnetic flux produced in the aforesaid manner. Thus, the magnetic resistance is reduced, so that the leakage flux lessens, and the inductance increases. Since the volume of the planar inductor also increases, however, value L/V is rather reduced.
- In this planar inductor, the ratio (t/l) of the thickness (t) of the ferromagnetic layer to the side length (l) thereof is preferably 1 × 10⁻³ or more for the following reason.
- Generally, when using the planar inductor according to the present invention on the output side of a DC-DC converter, a DC current is superposed, so that the planar inductor requires a good DC superposition characteristic. The superposed DC current is estimated at 0.2 A or more.
- In this planar inductor, the magnetic flux is supposed to flow in the planar direction of the ferromagnetic layers. In this case, the coefficient of planar diamagnetic field of the ferromagnetic layers influences the planar magnetic resistance. More specifically, if the coefficient of diamagnetic field is greater, then the magnetic resistance increases in proportion. Thus, the increase of the magnetic resistance produces the same effect as a planar magnetic gap, thereby improving the DC superposition characteristic of the inductance. Preferably, a high-permeability amorphous alloy should be used for the ferromagnetic layers.
- In a square planar inductor, for example, if the ratio of the thickness of each ferromagnetic layer to the side length thereof is greater, then the coefficient of planar diamagnetic field of the ferromagnetic layer increases in proportion. In other words, the greater the thickness of the ferromagnetic layer, or the shorter the side length, the greater the coefficient of diamagnetic field is. If the ratio between the thickness and the side length is 10⁻³ or more, the magnetic resistance increases, so that the DC superposition characteristic of the inductance is improved. If the spiral conductor coils or a laminated structure thereof and, therefore, the ferromagnetic layers on either side thereof are circular in shape, the magnetic resistance increases, thus improving the DC superposition characteristic of the inductance, when the ratio of the thickness of each ferromagnetic layer to the diameter thereof is 10⁻³ or more. In order to increase the thickness of the ferromagnetic layer, a laminated structure including a plurality of ferromagnetic ribbons may be used as the ferromagnetic layer, for example. The same effect may be also obtained with use of a planar inductor which has no laminate construction.
- According to a still further aspect of the present invention, there is provided a planar inductor which comprises spiral conductor coil means or a laminated structure including a plurality of spiral conductor coil means sandwiched between ferromagnetic layers each including a plurality of ferromagnetic ribbons, each of the ferromagnetic ribbons having a thickness of 100 »m or less.
- Preferably, the spiral conductor coil means are electrically connected in series with one another so that currents of the same direction flow through the conductor coil means.
- In the planar inductor constructed in this manner, the magnetic flux flows in the planar direction of the ferromagnetic layers. Therefore, if each ferromagnetic layer is formed of a plurality of ferromagnetic ribbons stacked in layers, as in this planar inductor, the general thickness of the ferromagnetic layer becomes greater, so that planar diamagnetic fields increase. Thus, the magnetic resistance can be enhanced, thereby improving the DC superposition characteristic of the inductance.
- The spiral conductor coils may be stacked in layers. In this case, however, it is advisable to dispose only the nsulating layers between the conductor coils, without interposing the ferromagnetic layers. This is because the existence of the ferromagnetic layers between the conductor coils is hardly conducive to the increase of the inductance, and instead, causes the general thickness of the planar inductor to increase, thereby lowering the inductance per unit volume.
- In the planar inductor constructed in this manner, the thickness of each of the ferromagnetic ribbons constituting each ferromagnetic layer is adjusted to 100 »m less for the following reason. Generally, when applying the planar inductor to a DC-DC converter or the like which is used with a frequency of 10 kHz or more, if the ribbon thickness exceeds 100 »m, the magnetic flux is prevented from penetrating the ferromagnetic layer by a skin effect. Thus, the inductance cannot increase in proportion to the increase of the thickness of the ferromagnetic ribbon, so that the inductance per unit volume is rather reduced. Preferably, the thickness of each ferromagnetic ribbon should be 4 »m or more. If the ribbon thickness is less than 4 »m, the ribbon cannot enjoy a sectional area large enough for the passage of all the magnetic flux which is produced as the currents flow through the spiral conductor coils. Thus, leakage flux increases, so that the inductance lowers considerably, and therefore, the inductance value per unit volume is reduced.
- In this planar inductor, moreover, a plurality of ferromagnetic ribbons are used to form each ferromagnetic layer because the DC superposition characteristic cannot be improved with use of only one ribbon for each ferromagnetic layer, as in the case of the prior art planar inductors. As the ferromagnetic ribbons used in each ferromagnetic layer are increased in number, the DC superposition characteristic is improved considerably. If the number exceeds ten, however, the effect of improvement is reduced. Thus, the volume increases for nothing, so that the inductance per unit volume lowers. Preferably, after all, two to ten ferromagnetic ribbons are used for the purpose.
- For the improvement of the DC superposition characteristic, moreover, the ratio of the thickness (t) of each ferromagnetic layer, composed of a plurality of ferromagnetic ribbons to the side length, should range from 2 × 10⁻³ to 1 × 10⁻².
- In a square planar inductor, for example, if the ratio of the thickness of each ferromagnetic layer to the side length thereof is greater, then the coefficient of planar diamagnetic field of the ferromagnetic layer increases in proportion. In other words, the greater the thickness of the ferromagnetic layer, or the shorter the side length, the greater the coefficient of diamagnetic field is. If the ratio between the thickness and the side length ranges from 2 × 10⁻³ to 1 × 10⁻², the magnetic resistance increases, so that the DC superposition characteristic of the inductance can be improved. If the spiral conductor coils or a laminated structure thereof and, therefore, the ferromagnetic layers on either side thereof are circular in shape, the magnetic resistance increases, thus improving the DC superposition characteristic of the inductance, when the ratio of the thickness of each ferromagnetic layer to the diameter thereof ranges from 2 × 10⁻³ to 1 × 10⁻².
- This invention can be more fully understood from the following detailed description when taken in conjunction with the accompanying drawings, in which:
- Fig. 1A is a plane view of a prior art planar inductor;
- Fig. 1B is a sectional view of the prior art planar inductor as taken along line A-A of Fig. 1A;
- Fig. 2 is a diagram for illustrating flux paths of the prior art planar inductor;
- Fig. 3A is a plane view of a planar inductor;
- Fig. 3B is a sectional view of the planar inductor as taken along line A-A of Fig. 3A;
- Fig. 4 is a diagram for illustrating a flux path of the planar inductor of Figures 3A and 3B;
- Fig. 5 shows characteristic curves indicative of relationships between the inductance and the frequency of the planar inductor;
- Fig. 6 shows characteristic curves indicative of a relationship between the inductance of the planar inductor shown in Figures 3A and 3B and the average thickness of a ferromagnetic ribbon and a relationship between the inductance per unit volume (L/V) and the average ribbon thickness;
- Fig. 7A is a plane view of a plan view of another inductor;
- Fig. 7B is a sectional view of the planar inductor of the other inductor as taken along line A-A of Fig. 7A;
- Fig. 8 is a diagram for illustrating flux paths of the planar inductor of Figures 7A and 7B;
- Figs. 9, 11 and 14 show characteristic curves indicative of relationships between the inductance and frequency of the planar inductor of Figures 7A and 7B;
- Figs. 10A, 12A and 15A are plan views of respective further planar inductors;
- Figs. 10B, 12B and 15B are sectional views of the planar inductors along lines A-A of Figs. 10A, 12A and 15A, respectively;
- Fig. 13 is a diagram for illustrating flux paths of the planar inductor of Figure 12;
- Fig. 16A is a plane view of a yet further planar inductor;
- Fig. 16B is a sectional view of the planar inductor as taken along line A-A of Fig. 16A;
- Fig. 17 shows characteristic curves indicative of relationships between the respective inductances of the planar inductor of Figures 16A and 16B and a planar inductor of Comparative Example 7 and the average ribbon thickness;
- Fig. 18 shows characteristic curves indicative of relationships between the inductances per unit volume (L/V) of the planar inductors of Figures 16A and 16B and Comparative Example 7 and the average ribbon thickness;
- Fig. 19 is a sectional view of a planar inductor according to a first embodiment of the present invention;
- Fig. 20 is a sectional view of a planar inductor prepared as a comparative example for the first embodiment;
- Fig. 21 shows characteristic curves indicative of the frequency characteristics of inductances L of the planar inductors of the first embodiment and the comparative example;
- Fig. 22 shows characteristic curves indicative of the frequency characteristics of the respective inductances per unit volume (L/V) of the planar inductors of the first embodiment and the comparative example;
- Fig. 23 shows characteristic curves indicative of relationships between the -superposed DC current and the inductance of the planar inductor of the first embodiment, obtained with use of the number of amorphous alloy ribbons as a parameter;
- Fig. 24 shows characteristic curves indicative of relationships between the superposed DC current and the ratio of the inductance produced when the superposed DC voltage is applied to the inductance produced when the superposed DC voltage is not applied, with respect to the planar inductor of the first embodiment, obtained with use of the number of amorphous alloy ribbons as the parameter;
- Fig. 25 shows a characteristic curve indicative of a relationship between the ratio of the thickness of the amorphous alloy ribbon to the side length thereof and the ratio of the inductance produced when a superposed DC current of 0.2 A is applied to the inductance produced when the superposed DC current is not applied, with respect to the planar inductor of the first embodiment;
- Fig. 26A is a plane view of a planar inductor according to a second embodiment of the present invention;
- Fig. 26B is a sectional view as taken along line A-A′ of Fig. 26A;
- Fig. 27 shows characteristic curves indicative of relationships between the superposed DC current and the inductance of the planar inductor of the second embodiment, obtained with use of the number of ferromagnetic ribbons as a parameter; and
- Fig. 28 shows a characteristic curve indicative of a relationship between the ratio of the thickness of the laminate of the ferromagnetic layers to the side length thereof and the ratio of the inductance produced when a superposed DC current of 0.2 A is applied to the inductance produced when the superposed DC current is not applied, with respect to the planar inductor of the second embodiment.
- Fig. 3A is a plane view of a planar inductor and Fig. 3B is a sectional view of the planar inductor as taken along line A-A of Fig. 3A. In these drawings, like reference numerals are used to designate the same portions as are included in the prior art planar inductor shown in Fig. 1. This planar inductor is constructed so that two pairs of
spiral conductor coils layers Ferromagnetic ribbons layers Conductor coils - Spiral conductor coils 1a, 1b, 1a′ and 1b′ are each formed of a two-layer coil which, obtained by etching a copper foil of 20 »m thickness, for example, has a 1-mm width, 1-mm coil pitch, and 10 turns.
- Insulating
layers -
Ferromagnetic ribbons - The components, including
spiral conductor coils - The path of
magnetic flux 6 of the planar inductor of Figs. 3A, 3B constructed in this manner is indicated by an arrowhead line in Fig. 4. The frequency characteristic of this planar inductor was actually examined. Characteristic curve I of Fig. 5 represents the result of the examination. - For comparison, two planar inductors, each composed of the same spiral conductor coils, insulating layers, and ferromagnetic ribbons as were used in the aforementioned inductor were simply connected electrically in series with each other (Comparative Example 1). The frequency characteristic of this comparative example was also examined. Curve II of Fig. 5 represents the examination result. In the inductors of Comparative Example 1, each ferromagnetic ribbon measures 25 mm by 25 mm.
- As seen from the results shown in Fig. 5, the planar inductor of Figs. 3A, 3B as compared with the two series-connected planar inductors of Comparative Example 1, was found to have a greater inductance value throughout the frequency band and, therefore, an improved inductance value per unit volume, thus enjoying very high efficiency.
- Alternative planar inductors for comparison (Comparative Example 2) were prepared. These inductors have the same construction as those of the aforementioned inductor, except that the ferromagnetic ribbons are formed of an Fe-based amorphous alloy with magnetostriction of about 8 × 10⁻⁶. The inductance of the inductors of Comparative Example 2 was substantially halved when they are bent slightly. In contrast with this, the planar inductor of Figs. 3A, 3B hardly exhibited any change although they were bent in the same manner. Thus, it was revealed that the inductance value of the planar inductor of Figs. 3A, 3B is stable even though the inductor is subjected to a stress produced while the components are being bonded together or a bending moment during use.
- Subsequently, the influence of the thickness of the ferromagnetic ribbons was examined on the planar inductor of Figs. 3A, 3B. In this case,
spiral conductor coils layer 3b, formed of a polyimide film of 25-»m thickness, is interposed between the layers, and are connected to one another through a through hole in the center. A polyimide film of 12-»m thickness is used for insulatinglayers -
Ferromagnetic ribbons
The effective permeability of this Co-based amorphous alloy is 2 × 10⁴ (1 kHz) or 1 × 10⁴ (100 kHz). - Fig. 6 shows the dependence of the inductance (L) on the thickness of
ferromagnetic ribbons - As seen from Fig. 6, inductance L tends to increase as the average thickness of
ferromagnetic ribbons - Fig. 7A is a plane view of another planar inductor and Fig. 7B is a sectional view of the inductor as taken along line A-A of Fig. 7A. This planar inductor is constructed so that two pairs of spiral conductor coils la and lb of the same shape are arranged in two layers, with insulating
layers Ferromagnetic ribbons layers Ferromagnetic substance 10 is disposed in the center of the coil assembly so as to be in contact withferromagnetic ribbons - Spiral conductor coils 1a and 1b are each formed of a two-layer coil which, obtained by etching a copper foil of 20-»m thickness, for example, has a 1-mm width, 1-mm coil pitch, and 10 turns.
- Insulating
layers -
Ferromagnetic ribbons -
Ferromagnetic substance 10 is composed of four or five pieces of 2 mm by 2 mm which are obtained by cutting down a Co-based amorphous alloy ribbon, for example. - The components, including spiral conductor coils la and lb, are assembled by being kept at a temperature of 170°C and a pressure of 5 kg/cm² for about 10 minutes, for example.
- The path of
magnetic flux 6 of the planar inductor of Figs. 7A, 7B as constructed in this manner, is indicated by an arrowhead line in Fig. 8. The frequency characteristic of this planar inductor was actually examined. Characteristic curve I of Fig. 9 represents the result of the examination. - For comparison, a planar inductor, composed of the same spiral conductor coils, insulating layers, and ferromagnetic ribbons as are used in Figs. 7A, 7B, was formed having a gap portion without a ferromagnetic substance in the center of the coil assembly (Comparative Example 3). The frequency characteristic of this comparative example was also examined. Curve II of Fig. 9 represents the examination result.
- As seen from the results shown in Fig. 9, the planar inductor of Figs. 7A, 7B in which the gap portion in the center of the coil assembly is short-circuited by means of
ferromagnetic substance 10 set therein, was found to have a greater inductance value throughout the frequency band and, therefore, an improved inductance value per unit volume, as compared with Comparative Example 3, thus enjoying very high efficiency. - An alternative planar inductor for comparison (Comparative Example 4) was prepared. This inductor has the same construction as that of Comparative Example 3, except that the ferromagnetic ribbons are formed of an Fe-based amorphous alloy with nagnetostriction of about 8 × 10⁻⁶. The inductance of the inductor of Comparative Example 4 was substantially deteriorated when they are bent slightly. In contrast with this, the planar inductor of Figs. 7A, 7B hardly exhibited any change although they were bent in the same manner. Thus, it was revealed that the inductance value of the planar inductor of Figs. 7A, 7B is stable even though the inductor is subjected to a stress produced while the components are being bonded together or a bending moment during use.
- A planar inductor was manufactured, as shown in Figs. 10A, 10B. Two planar inductors corresponding to those shown in Figs. 7A, 7B are arranged so that two pairs of
spiral conductor coils Ferromagnetic ribbons layers Conductor coils - For comparison, a planar inductor, composed of the same spiral conductor coils, insulating layers, and ferromagnetic ribbons as are used in the inductor of Figs. 10A, 10B was formed having a gap portion without a ferromagnetic substance in the center of the coil assembly (Comparative Example 5). The frequency characteristic of this comparative example was also examined. Curve II′ of Fig. 11 represents the examination result.
- As seen from the results shown in Fig. 11, the planar inductor of Figs. 10A, 10B as compared with Comparative Example 5, was found to have a greater inductance value throughout the frequency band and, therefore, an improved inductance value per unit volume.
- A further planar inductor was manufactured, as shown in Figs. 12A, 12B. This inductor has the same construction as that of Comparative Example 5, except that
ferromagnetic substance 10" is disposed flush with spiral conductor coils la and lb so as to surround the outer periphery of the coil assembly. - The path of
magnetic flux 6 of this planar inductor constructed in this manner is indicated by an arrowhead line in Fig. 13. The frequency characteristic of this planar inductor was actually examined. Characteristic curve I" of Fig. 14 represents the result of the examination. - For comparison, a planar inductor, composed of the same spiral conductor coils, insulating layers, and ferromagnetic ribbons as are used in the inductor of Figs. 12A, 12B, was formed having a gap portion without a ferromagnetic substance surrounding the outer periphery of the coil assembly (Comparative Example 6). The frequency characteristic of this comparative example was also examined. Curve II" of Fig. 14 represents the examination result.
- As seen from the results shown in Fig. 14, the planar inductor of Figs. 12A, 12B as compared with Comparative Example 6, was found to have a greater inductance value throughout the frequency band and, therefore, an improved inductance value per unit volume.
- A still further planar inductor was manufactured, as shown in Figs. 15A, 15B. In this inductor,
ferromagnetic substance 10‴ covers those regions where insulatinglayers ferromagnetic ribbons - The influence of the thickness of the ferromagnetic ribbons was examined on the planar inductor with the configuration shown in Figs. 16A, 16B. In this planar inductor,
ferromagnetic substance 10 is disposed in the center of an assembly of spiral conductor coils la and lb, whileferromagnetic substance 10‴ is disposed in the region surrounding the outer periphery of the coil assembly. In this case, conductor coils la and lb, which are formed by etching a thick copper foil of 35-»m thickness, have a width of 0.25 mm, coil pitch of 0.25 mm, 40 turns, and external size of 20 mm by 20 mm. These coils are arranged in two layers so that insulatinglayer 3b, formed of a polyimide film of 25-»m thickness, is interposed between the layers, and are connected to one another through a through hole in the center. A polyimide film of 12-»m thickness is used for insulatinglayers -
Ferromagnetic ribbons
The effective permeability of this Co-based amorphous alloy is 2 × 10⁴ (1 kHz) or 1 × 10⁴ (100 kHz). -
Ferromagnetic substance 10, which is disposed in the center of the coil assembly, is formed of six ribbons in layers which, having an external size of 2 mm by 2 mm, are obtained by cutting down a Co-based amorphous alloy having the aforesaid composition and an average thickness of 20 »m.Ferromagnetic substance 10‴, which is disposed outside the outer periphery ofspiral conductor coils 1a and 1b, is formed of six frame-shaped ribbons in layers which, having an internal size (indicated by X in Fig. 16A) of 21 mm and an external size (indicated by Y) of 25 mm, are obtained by cutting down a Co-based amorphous alloy having the aforesaid composition and an average thickness of 20 »m. - For comparison, five planar inductors (Comparative Example 7) were prepared. These inductors, whose
ferromagnetic ribbons - Fig. 17 shows the dependence of the inductance (L) on the thickness of
ferromagnetic ribbons - As seen from Figs. 17 and 18, inductance L tends to increase as the average thickness of
ferromagnetic ribbons ferromagnetic substances ferromagnetic substances - It was ascertained that the same results as are shown in Figs. 17 and 18 can be obtained from the planar inductor of Figs. 10A, 10B in which the two spiral conductor coils are arranged flush with each other and electrically connected so that currents of opposite directions flow through the coils.
- The present invention will now be explained in more detail by way of the following description of two embodiments thereof.
- Fig. 19 is a sectional view of a planar inductor according to a first embodiment of the present invention, and Fig. 20 is a sectional view of a planar inductor prepared as a comparative example for comparison therewith. In either case, the plane view of the inductor resembles Fig. 1A and, therefore, is omitted. In Figs. 19 and 20, each spiral
conductor coil assembly 1 is formed ofspiral coils Coils layer 3b) of 25-»m thickness and Cu foils of 35-»m thickness formed on either side thereof and connected to each other through center throughhole 4, and then etching the Cu foils. - In manufacturing the planar inductor of the first embodiment as shown in Fig. 19, three
conductor coil assemblies 1 with the aforementioned configuration were stacked in layers with polyimide films (insulatinglayers 3d) of 7-»m thickness between them. The resulting laminated structure was sandwiched between two square ribbons (ferromagnetic layers layers 3e and 3f) of 7-»m between the laminated structure and their corresponding ribbons. Each square ribbon, whose side is 25 mm long, was cut out from a Co-based high-permeability amorphous alloy ribbon which, having a thickness of 18 »m and a width of 25 mm, was formed by simple rolling. An instantaneous bonding agent was applied to the side faces of the resulting planar inductor with the laminate construction, in order to bond the individual layers together. - For comparison, three planar inductors (Comparative Example 8) were stacked in layers, as shown in Fig. 20. Each of these inductors includes spiral
conductor coil assembly 1, which is sandwiched between two 25-mm square ribbons (ferromagnetic layers layers Coil assembly 1 is composed ofspiral coils layer 3b) of 25-»m thickness sandwiched between the coils. An instantaneous bonding agent was applied to the side faces of the resulting planar inductor with the laminate construction. - In either of the planar inductors of the first embodiment and Comparative Example 8, three spiral
conductor coil assemblies 1 are connected to one another so that currents of the same phase flow through them. - The thicknesses of the planar inductors of the first Embodiment and Comparative Example 8 are 510 »m and 605 »m, respectively.
- Fig. 21 shows the frequency characteristic of inductance L of each planar inductor, and Fig. 22 shows that of inductance L/V per unit volume.
- As seen from Fig. 21, the values of inductance L of the planar inductors of the first embodiment and Comparative Example 8 are substantially equal. On the high-frequency side, however, the inductor of the first embodiment, which is thinner, is rather greater in inductance.
- As seen from Fig. 22, moreover, the value of inductance L/V per unit volume of the planar inductor of the first embodiment is about 20% greater than that of the planar inductor of Comparative Example 7.
- The DC superposition characteristic was examined on planar inductors which have the same fundamental configuration as the one shown in Fig. 19, and in which one to ten square Co-based high-permeability amorphous alloy ribbons, having a thickness of 18 »m and a
side 25 »m long, are used asferromagnetic layers - Fig. 23 shows characteristic curves indicative of relationships between the superposed DC current and the inductance, obtained with use of the number of amorphous alloy ribbons as a parameter. Fig. 24 shows characteristic curves indicative of relationships between the superposed DC current and the ratio of the inductance produced when the superposed DC current is applied to the inductance produced when the superposed current is not applied, obtained with use of the number of amorphous alloy ribbons as the parameter. Fig. 25 shows a characteristic curve indicative of a relationship between the ratio of the thickness of the laminate of the amorphous alloy ribbons to the side length thereof and the ratio of the inductance produced when a superposed DC current of 0.2 A is applied to the inductance produced when the superposed DC current is not applied. All the inductance values were measured at 50 kHz.
- As shown in Fig. 23, even if the number (n) of ribbons is increased, inductance L₀ produced when the superposed DC current is not applied can only attain a value much smaller than n times the value obtained when n equals 1. As seen from Figs. 23 and 24, however, if number n becomes greater, then the rate of reduction of the inductance with the increase of the superposed DC current is lowered in proportion, so that the DC superposition characteristic is improved.
- As seen from Fig. 25, moreover, if the ratio (t/1) of the thickness of the ribbon laminate to the side length thereof is smaller than 10⁻³, the ratio (L0.2/L₀) of the inductance produced when the superposed DC current of 0.2 A is applied to the inductance produced when the superposed DC current is not applied is 0.3 or less, thus indicating a poor DC superposition characteristic. If t/l is 10⁻³ or more, on the other hand, L0.2/L₀ is greater than 0.3, that is, great enough for practical use. If t/l exceeds 3.5 × 10⁻³ moreover, L0.2/L₀ is 0.8 or more, so that the DC superposition characteristic is considerably improved.
- Fig. 26A is a plane view of a planar inductor according to a second embodiment of the present invention, and Fig. 26B is a sectional view as taken along line A-A′ of Fig. 26A. In Fig. 26, spiral
conductor coil assembly 1 is formed ofspiral coils Coils layer 3b) of 25-»m thickness and Cu foils of 35-»m thickness formed on either side thereof and connected to each other through center throughhole 4, and then etching the Cu foils. The planar inductor of the second embodiment is constructed so thatconductor coil assembly 1 with the aforesaid configuration is sandwiched between two sets of ferromagnetic layers each including a plurality of square ribbons (ferromagnetic ribbons layers terminals - For comparison, a conventional planar inductor (Comparative Example 9), which includes only one ferromagnetic ribbon on each side of the coil assembly, was prepared using the same materials as aforesaid.
- Fig. 27 shows relationships between the superposed DC current and the inductance of these planar inductors, obtained with use of the number of ferromagnetic ribbons as a parameter. The inductance values were measured at 50 kHz.
- As seen from Fig. 27, if number n becomes greater, then the rate of reduction of the inductance with the increase of the superposed DC current is lowered in proportion, so that the DC superposition characteristic is improved. If n is 15, however, substantially the same result is obtained as in the case where n is 10. Thus, it is indicated that the improvement effect of the DC superposition characteristic hardly makes any change if the ferromagnetic ribbons used exceed ten in number.
- Fig. 28 shows a relationship between the ratio of the thickness of the laminate of the ferromagnetic layer to the side length thereof and the ratio of the inductance (L0.2) produced when a superposed DC current of 0.2 A is applied to the inductance (L₀) produced when the superposed DC current is not applied, with respect to the aforementioned planar inductors.
- As seen from Fig. 28, if ratio t/l is smaller than 10⁻³, ratio L0.2/L₀ is smaller than 0.5, thus indicating a poor DC superposition characteristic. If t/l is 3 × 10⁻³ or more, on the other hand, L0.2/L₀ is 0.85 or more, so that the DC superposition characteristic is considerably improved.
- Furthermore, a planar inductor according to the present was applied to a DC-DC converter of a 5 V/2 W type, and its efficiency was examined with use of 15 V input voltage and 0.2 A output current. Thereupon, efficiency η was found to be about 60 % when n is 1, while it increased to 71 % when n was increased to 5.
Claims (6)
- A planar inductor comprising spiral conductor coil means (5a, 5b) sandwiched between ferromagnetic layers (2a, 2b) with insulating layers interposed therebetween, characterized in that each said ferromagnetic layer includes a plurality of ferromagnetic sheets each having a thickness of 100 »m or less.
- A planar inductor according to claim 1, characterized in that said inductor comprises a plurality of spiral conductor coil means (5a, 5b) laminated one upon the other and electrically connected in series with one another so that currents of the same direction flow through these conductor coil means.
- A planar inductor according to claim 1, further characterized in that the absolute value of magnetostriction of each said ferromagnetic sheet is 1 x 10⁻⁶ or less.
- A planar inductor according to claim 1, further characterized in that said ferromagnetic sheets (2a, 2b) are formed of an amorphous magnetic alloy.
- A planar inductor according to claim 1, further characterized in that the average thickness of each said ferromagnetic sheet ranges from 4 to 20 »m.
- A DC-DC converter characterised by comprising a planar inductor comprising spiral conductor coil means (5a, 5b) sandwiched between ferromagnetic layers (2a, 2b) with insulating layers interposed therebetween, wherein each said ferromagnetic layer includes a plurality of ferromagnetic sheets each having a thickness of 100 »m or less.
Applications Claiming Priority (12)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP24547287 | 1987-09-29 | ||
JP24547387 | 1987-09-29 | ||
JP245473/87 | 1987-09-29 | ||
JP245472/87 | 1987-09-29 | ||
JP6226288A JPH01157508A (en) | 1987-09-29 | 1988-03-16 | Plane inductor |
JP63062261A JPH01157507A (en) | 1987-09-29 | 1988-03-16 | Plane inductor |
JP62261/88 | 1988-03-16 | ||
JP62262/88 | 1988-03-16 | ||
JP142043/88 | 1988-06-09 | ||
JP63142043A JP2958892B2 (en) | 1988-06-09 | 1988-06-09 | Planar inductor |
JP151779/88 | 1988-06-20 | ||
JP63151779A JP2958893B2 (en) | 1988-06-20 | 1988-06-20 | Planar inductor |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0310396A1 EP0310396A1 (en) | 1989-04-05 |
EP0310396B1 true EP0310396B1 (en) | 1995-07-19 |
Family
ID=27550882
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP88309056A Expired - Lifetime EP0310396B1 (en) | 1987-09-29 | 1988-09-29 | Planar inductor |
Country Status (4)
Country | Link |
---|---|
US (1) | US4959631A (en) |
EP (1) | EP0310396B1 (en) |
KR (1) | KR910003292B1 (en) |
DE (1) | DE3854177T2 (en) |
Families Citing this family (168)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0361967B1 (en) | 1988-09-30 | 1995-12-20 | Kabushiki Kaisha Toshiba | Planar inductor |
US5152480A (en) * | 1989-11-15 | 1992-10-06 | The B. F. Goodrich Company | Planar coil construction |
US5142767A (en) * | 1989-11-15 | 1992-09-01 | Bf Goodrich Company | Method of manufacturing a planar coil construction |
JP3048592B2 (en) * | 1990-02-20 | 2000-06-05 | ティーディーケイ株式会社 | Laminated composite parts |
KR960006848B1 (en) * | 1990-05-31 | 1996-05-23 | 가부시끼가이샤 도시바 | Plane magnetic elements |
DE4019241A1 (en) * | 1990-06-15 | 1991-12-19 | Telefunken Electronic Gmbh | Energy and signal transmission system - for transmitting measurement signals from vehicle tyres |
US5639391A (en) * | 1990-09-24 | 1997-06-17 | Dale Electronics, Inc. | Laser formed electrical component and method for making the same |
US5083236A (en) * | 1990-09-28 | 1992-01-21 | Motorola, Inc. | Inductor structure with integral components |
GB2252208B (en) * | 1991-01-24 | 1995-05-03 | Burr Brown Corp | Hybrid integrated circuit planar transformer |
US5402098A (en) * | 1991-03-25 | 1995-03-28 | Satosen Co., Ltd. | Coil |
US5349743A (en) * | 1991-05-02 | 1994-09-27 | At&T Bell Laboratories | Method of making a multilayer monolithic magnet component |
JP3197022B2 (en) * | 1991-05-13 | 2001-08-13 | ティーディーケイ株式会社 | Multilayer ceramic parts for noise suppressor |
CA2072277A1 (en) * | 1991-07-03 | 1993-01-04 | Nobuo Shiga | Inductance element |
US5363080A (en) * | 1991-12-27 | 1994-11-08 | Avx Corporation | High accuracy surface mount inductor |
JP3114323B2 (en) * | 1992-01-10 | 2000-12-04 | 株式会社村田製作所 | Multilayer chip common mode choke coil |
US5414401A (en) * | 1992-02-20 | 1995-05-09 | Martin Marietta Corporation | High-frequency, low-profile inductor |
JP3102125B2 (en) * | 1992-02-28 | 2000-10-23 | 富士電機株式会社 | Thin film magnetic element |
DE4306655C2 (en) * | 1992-03-04 | 1997-04-30 | Toshiba Kawasaki Kk | Method of manufacturing a planar induction element |
US5302932A (en) * | 1992-05-12 | 1994-04-12 | Dale Electronics, Inc. | Monolythic multilayer chip inductor and method for making same |
JP3141562B2 (en) * | 1992-05-27 | 2001-03-05 | 富士電機株式会社 | Thin film transformer device |
US5304767A (en) * | 1992-11-13 | 1994-04-19 | Gas Research Institute | Low emission induction heating coil |
EP0608127A1 (en) * | 1993-01-22 | 1994-07-27 | AT&T Corp. | Insulation system for magnetic windings having stacked planar conductors |
DE4306416A1 (en) * | 1993-03-02 | 1994-09-08 | Kolbe & Co Hans | Coil structure for a printed circuit board arrangement |
US5583424A (en) * | 1993-03-15 | 1996-12-10 | Kabushiki Kaisha Toshiba | Magnetic element for power supply and dc-to-dc converter |
US5430613A (en) * | 1993-06-01 | 1995-07-04 | Eaton Corporation | Current transformer using a laminated toroidal core structure and a lead frame |
JPH07268610A (en) * | 1994-03-28 | 1995-10-17 | Alps Electric Co Ltd | Soft magnetic alloy thin film |
JP3116713B2 (en) * | 1994-03-31 | 2000-12-11 | 株式会社村田製作所 | Electronic components with built-in inductor |
KR100231356B1 (en) * | 1994-09-12 | 1999-11-15 | 모리시타요이찌 | Laminated ceramic chip inductor and its manufacturing method |
US6911887B1 (en) * | 1994-09-12 | 2005-06-28 | Matsushita Electric Industrial Co., Ltd. | Inductor and method for producing the same |
KR100276052B1 (en) * | 1994-10-04 | 2000-12-15 | 모리시타 요이찌 | Manufacturing method of transfer conductor and of laminating green sheet |
CH689063A5 (en) | 1994-10-09 | 1998-08-31 | Wuest Ernst Menu System | Kochgeraet. |
US5572779A (en) * | 1994-11-09 | 1996-11-12 | Dale Electronics, Inc. | Method of making an electronic thick film component multiple terminal |
JP3152088B2 (en) * | 1994-11-28 | 2001-04-03 | 株式会社村田製作所 | Manufacturing method of coil parts |
DE4442994A1 (en) | 1994-12-02 | 1996-06-05 | Philips Patentverwaltung | Planar inductance |
JPH0936312A (en) * | 1995-07-18 | 1997-02-07 | Nec Corp | Inductance element and its manufacture |
JPH0983104A (en) * | 1995-09-12 | 1997-03-28 | Murata Mfg Co Ltd | Circuit board with built-in coil |
US5849355A (en) * | 1996-09-18 | 1998-12-15 | Alliedsignal Inc. | Electroless copper plating |
KR970023498A (en) * | 1995-10-12 | 1997-05-30 | 서두칠 | Coil Assembly of Flyback Transformer |
JP2904086B2 (en) * | 1995-12-27 | 1999-06-14 | 日本電気株式会社 | Semiconductor device and manufacturing method thereof |
AU3597897A (en) * | 1996-07-29 | 1998-02-20 | Motorola, Inc. | Low radiation planar inductor/transformer and method |
US6073339A (en) * | 1996-09-20 | 2000-06-13 | Tdk Corporation Of America | Method of making low profile pin-less planar magnetic devices |
JP3600415B2 (en) * | 1997-07-15 | 2004-12-15 | 株式会社東芝 | Distributed constant element |
JP3615024B2 (en) | 1997-08-04 | 2005-01-26 | 株式会社村田製作所 | Coil parts |
US6039371A (en) * | 1997-08-04 | 2000-03-21 | Smith; Mark | Vacuum stretching and gripping tool and method for laying flooring |
US5969590A (en) * | 1997-08-05 | 1999-10-19 | Applied Micro Circuits Corporation | Integrated circuit transformer with inductor-substrate isolation |
US20030042571A1 (en) * | 1997-10-23 | 2003-03-06 | Baoxing Chen | Chip-scale coils and isolators based thereon |
US6013939A (en) * | 1997-10-31 | 2000-01-11 | National Scientific Corp. | Monolithic inductor with magnetic flux lines guided away from substrate |
GB2332100A (en) * | 1997-12-02 | 1999-06-09 | David Vail | An insulated winding arrangement |
JP3712163B2 (en) * | 1997-12-18 | 2005-11-02 | 株式会社村田製作所 | Coil parts design method |
US6249205B1 (en) * | 1998-11-20 | 2001-06-19 | Steward, Inc. | Surface mount inductor with flux gap and related fabrication methods |
US6566731B2 (en) | 1999-02-26 | 2003-05-20 | Micron Technology, Inc. | Open pattern inductor |
FR2790328B1 (en) * | 1999-02-26 | 2001-04-20 | Memscap | INDUCTIVE COMPONENT, INTEGRATED TRANSFORMER, IN PARTICULAR INTENDED TO BE INCORPORATED IN A RADIOFREQUENCY CIRCUIT, AND INTEGRATED CIRCUIT ASSOCIATED WITH SUCH AN INDUCTIVE COMPONENT OR INTEGRATED TRANSFORMER |
KR100349419B1 (en) * | 1999-07-27 | 2002-08-19 | 학교법인 한국정보통신학원 | Dual-layer spiral inductor |
US6856228B2 (en) * | 1999-11-23 | 2005-02-15 | Intel Corporation | Integrated inductor |
US6891461B2 (en) * | 1999-11-23 | 2005-05-10 | Intel Corporation | Integrated transformer |
US6870456B2 (en) * | 1999-11-23 | 2005-03-22 | Intel Corporation | Integrated transformer |
JP2001333493A (en) * | 2000-05-22 | 2001-11-30 | Furukawa Electric Co Ltd:The | Plane loudspeaker |
US6587025B2 (en) * | 2001-01-31 | 2003-07-01 | Vishay Dale Electronics, Inc. | Side-by-side coil inductor |
US7196604B2 (en) * | 2001-05-30 | 2007-03-27 | Tt Electronics Technology Limited | Sensing apparatus and method |
US6768409B2 (en) * | 2001-08-29 | 2004-07-27 | Matsushita Electric Industrial Co., Ltd. | Magnetic device, method for manufacturing the same, and power supply module equipped with the same |
US20030112110A1 (en) * | 2001-09-19 | 2003-06-19 | Mark Pavier | Embedded inductor for semiconductor device circuit |
FR2839582B1 (en) * | 2002-05-13 | 2005-03-04 | St Microelectronics Sa | INDUCTANCE AT MIDDLE POINT |
DE10243197B4 (en) | 2002-09-18 | 2011-05-05 | Infineon Technologies Ag | Digital signal transmission method |
GB2394293A (en) * | 2002-10-16 | 2004-04-21 | Gentech Invest Group Ag | Inductive sensing apparatus and method |
WO2004036147A2 (en) * | 2002-10-16 | 2004-04-29 | Tt Electronics Technology Limited | Position sensing apparatus and method |
GB0303627D0 (en) * | 2003-02-17 | 2003-03-19 | Sensopad Technologies Ltd | Sensing method and apparatus |
JP3800555B2 (en) * | 2003-04-24 | 2006-07-26 | 松下電器産業株式会社 | High frequency circuit |
EP2302850A1 (en) * | 2003-04-30 | 2011-03-30 | Analog Devices, Inc. | Signal isolators using micro-transformers |
US7852185B2 (en) * | 2003-05-05 | 2010-12-14 | Intel Corporation | On-die micro-transformer structures with magnetic materials |
US6927664B2 (en) * | 2003-05-16 | 2005-08-09 | Matsushita Electric Industrial Co., Ltd. | Mutual induction circuit |
US7061359B2 (en) * | 2003-06-30 | 2006-06-13 | International Business Machines Corporation | On-chip inductor with magnetic core |
US20070001796A1 (en) * | 2003-08-26 | 2007-01-04 | Eberhardt Waffenschmidt | Printed circuit board with integrated inductor |
TWM249190U (en) * | 2003-12-26 | 2004-11-01 | Hung-Wen Lin | Laminated chip inductor structure |
US8155018B2 (en) * | 2004-03-03 | 2012-04-10 | Qualcomm Atheros, Inc. | Implementing location awareness in WLAN devices |
US7242274B2 (en) * | 2004-03-03 | 2007-07-10 | Atheros Communications, Inc. | Inductor layout using step symmetry for inductors |
US20050231752A1 (en) * | 2004-04-16 | 2005-10-20 | Nokia Corporation | Image data transfer system and method |
US7737871B2 (en) * | 2004-06-03 | 2010-06-15 | Silicon Laboratories Inc. | MCU with integrated voltage isolator to provide a galvanic isolation between input and output |
US7421028B2 (en) * | 2004-06-03 | 2008-09-02 | Silicon Laboratories Inc. | Transformer isolator for digital power supply |
US7447492B2 (en) * | 2004-06-03 | 2008-11-04 | Silicon Laboratories Inc. | On chip transformer isolator |
US8198951B2 (en) | 2004-06-03 | 2012-06-12 | Silicon Laboratories Inc. | Capacitive isolation circuitry |
US7376212B2 (en) * | 2004-06-03 | 2008-05-20 | Silicon Laboratories Inc. | RF isolator with differential input/output |
US8169108B2 (en) | 2004-06-03 | 2012-05-01 | Silicon Laboratories Inc. | Capacitive isolator |
US7902627B2 (en) * | 2004-06-03 | 2011-03-08 | Silicon Laboratories Inc. | Capacitive isolation circuitry with improved common mode detector |
US7821428B2 (en) * | 2004-06-03 | 2010-10-26 | Silicon Laboratories Inc. | MCU with integrated voltage isolator and integrated galvanically isolated asynchronous serial data link |
US7460604B2 (en) * | 2004-06-03 | 2008-12-02 | Silicon Laboratories Inc. | RF isolator for isolating voltage sensing and gate drivers |
US7577223B2 (en) * | 2004-06-03 | 2009-08-18 | Silicon Laboratories Inc. | Multiplexed RF isolator circuit |
US7738568B2 (en) * | 2004-06-03 | 2010-06-15 | Silicon Laboratories Inc. | Multiplexed RF isolator |
US7302247B2 (en) * | 2004-06-03 | 2007-11-27 | Silicon Laboratories Inc. | Spread spectrum isolator |
US8441325B2 (en) * | 2004-06-03 | 2013-05-14 | Silicon Laboratories Inc. | Isolator with complementary configurable memory |
JP2006032587A (en) * | 2004-07-15 | 2006-02-02 | Matsushita Electric Ind Co Ltd | Inductance component and its manufacturing method |
JP2008509418A (en) * | 2004-08-09 | 2008-03-27 | センソパッド リミテッド | Detection apparatus and detection method |
KR100768919B1 (en) * | 2004-12-23 | 2007-10-19 | 삼성전자주식회사 | Apparatus and method for power generation |
US7598838B2 (en) * | 2005-03-04 | 2009-10-06 | Seiko Epson Corporation | Variable inductor technique |
US7436277B2 (en) * | 2005-06-01 | 2008-10-14 | Intel Corporation | Power transformer |
US8134548B2 (en) | 2005-06-30 | 2012-03-13 | Micron Technology, Inc. | DC-DC converter switching transistor current measurement technique |
DE102005039379B4 (en) * | 2005-08-19 | 2010-05-27 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Magnetic element with spiral coil (s), arrays of such devices and method for their preparation |
JP4965116B2 (en) * | 2005-12-07 | 2012-07-04 | スミダコーポレーション株式会社 | Flexible coil |
US7719305B2 (en) * | 2006-07-06 | 2010-05-18 | Analog Devices, Inc. | Signal isolator using micro-transformers |
FR2911992A1 (en) * | 2007-01-30 | 2008-08-01 | St Microelectronics Sa | Multilevel inductive element for e.g. passive filter, has plane windings formed in N number of lower conductive levels of circuit with respect to specific number of windings, where two of windings are interdigitized in same level |
US8253523B2 (en) * | 2007-10-12 | 2012-08-28 | Via Technologies, Inc. | Spiral inductor device |
US20090171346A1 (en) * | 2007-12-28 | 2009-07-02 | Greg Leyh | High conductivity inductively equalized electrodes and methods |
US8172835B2 (en) | 2008-06-05 | 2012-05-08 | Cutera, Inc. | Subcutaneous electric field distribution system and methods |
US20090306647A1 (en) * | 2008-06-05 | 2009-12-10 | Greg Leyh | Dynamically controllable multi-electrode apparatus & methods |
US20100022999A1 (en) * | 2008-07-24 | 2010-01-28 | Gollnick David A | Symmetrical rf electrosurgical system and methods |
JP2010160142A (en) * | 2008-12-09 | 2010-07-22 | Renesas Electronics Corp | Signaling method, method of manufacturing semiconductor device, semiconductor device, and tester system |
US9208942B2 (en) | 2009-03-09 | 2015-12-08 | Nucurrent, Inc. | Multi-layer-multi-turn structure for high efficiency wireless communication |
US9232893B2 (en) | 2009-03-09 | 2016-01-12 | Nucurrent, Inc. | Method of operation of a multi-layer-multi-turn structure for high efficiency wireless communication |
US9439287B2 (en) | 2009-03-09 | 2016-09-06 | Nucurrent, Inc. | Multi-layer wire structure for high efficiency wireless communication |
US9444213B2 (en) | 2009-03-09 | 2016-09-13 | Nucurrent, Inc. | Method for manufacture of multi-layer wire structure for high efficiency wireless communication |
US9300046B2 (en) | 2009-03-09 | 2016-03-29 | Nucurrent, Inc. | Method for manufacture of multi-layer-multi-turn high efficiency inductors |
US11476566B2 (en) | 2009-03-09 | 2022-10-18 | Nucurrent, Inc. | Multi-layer-multi-turn structure for high efficiency wireless communication |
US9306358B2 (en) | 2009-03-09 | 2016-04-05 | Nucurrent, Inc. | Method for manufacture of multi-layer wire structure for high efficiency wireless communication |
US8855786B2 (en) | 2009-03-09 | 2014-10-07 | Nucurrent, Inc. | System and method for wireless power transfer in implantable medical devices |
US8451032B2 (en) | 2010-12-22 | 2013-05-28 | Silicon Laboratories Inc. | Capacitive isolator with schmitt trigger |
JP6215518B2 (en) * | 2011-08-26 | 2017-10-18 | ローム株式会社 | Magnetic metal substrate and inductance element |
KR101550591B1 (en) | 2011-09-07 | 2015-09-07 | 티디케이가부시기가이샤 | Laminated coil component |
US20130068499A1 (en) * | 2011-09-15 | 2013-03-21 | Nucurrent Inc. | Method for Operation of Multi-Layer Wire Structure for High Efficiency Wireless Communication |
US8717136B2 (en) | 2012-01-10 | 2014-05-06 | International Business Machines Corporation | Inductor with laminated yoke |
US20130257575A1 (en) * | 2012-04-03 | 2013-10-03 | Alexander Timashov | Coil having low effective capacitance and magnetic devices including same |
US9064628B2 (en) | 2012-05-22 | 2015-06-23 | International Business Machines Corporation | Inductor with stacked conductors |
US8754500B2 (en) * | 2012-08-29 | 2014-06-17 | International Business Machines Corporation | Plated lamination structures for integrated magnetic devices |
CN104871307B (en) * | 2012-12-19 | 2018-01-02 | 瑞萨电子株式会社 | Semiconductor device |
EP2779181B1 (en) * | 2013-03-12 | 2018-09-26 | NuCurrent, Inc. | Multi-layer-multi-turn structure for high efficiency inductors |
US9293997B2 (en) | 2013-03-14 | 2016-03-22 | Analog Devices Global | Isolated error amplifier for isolated power supplies |
KR20140132105A (en) * | 2013-05-07 | 2014-11-17 | 삼성전기주식회사 | Common mode filter and method of manufacturing the same |
US10510476B2 (en) | 2013-09-27 | 2019-12-17 | Taiwan Semiconductor Manufacturing Company, Ltd. | Slow wave inductive structure and method of forming the same |
US9502168B1 (en) * | 2013-11-15 | 2016-11-22 | Altera Corporation | Interleaved T-coil structure and a method of manufacturing the T-coil structure |
JP6221736B2 (en) * | 2013-12-25 | 2017-11-01 | 三菱電機株式会社 | Semiconductor device |
JP6284797B2 (en) * | 2014-03-20 | 2018-02-28 | 新光電気工業株式会社 | Inductor, coil substrate, and method of manufacturing coil substrate |
DE102014207890A1 (en) * | 2014-04-28 | 2015-07-30 | Continental Automotive Gmbh | Foreign object detection device and power inductive charging device |
US10270630B2 (en) | 2014-09-15 | 2019-04-23 | Analog Devices, Inc. | Demodulation of on-off-key modulated signals in signal isolator systems |
US9660848B2 (en) | 2014-09-15 | 2017-05-23 | Analog Devices Global | Methods and structures to generate on/off keyed carrier signals for signal isolators |
US10536309B2 (en) | 2014-09-15 | 2020-01-14 | Analog Devices, Inc. | Demodulation of on-off-key modulated signals in signal isolator systems |
DE102014221568A1 (en) * | 2014-10-23 | 2016-04-28 | Siemens Aktiengesellschaft | Transformer and method for operating a transformer |
US9998301B2 (en) | 2014-11-03 | 2018-06-12 | Analog Devices, Inc. | Signal isolator system with protection for common mode transients |
US9960629B2 (en) | 2015-08-07 | 2018-05-01 | Nucurrent, Inc. | Method of operating a single structure multi mode antenna for wireless power transmission using magnetic field coupling |
US10636563B2 (en) | 2015-08-07 | 2020-04-28 | Nucurrent, Inc. | Method of fabricating a single structure multi mode antenna for wireless power transmission using magnetic field coupling |
US10658847B2 (en) | 2015-08-07 | 2020-05-19 | Nucurrent, Inc. | Method of providing a single structure multi mode antenna for wireless power transmission using magnetic field coupling |
US9941729B2 (en) | 2015-08-07 | 2018-04-10 | Nucurrent, Inc. | Single layer multi mode antenna for wireless power transmission using magnetic field coupling |
US9960628B2 (en) | 2015-08-07 | 2018-05-01 | Nucurrent, Inc. | Single structure multi mode antenna having a single layer structure with coils on opposing sides for wireless power transmission using magnetic field coupling |
US9948129B2 (en) | 2015-08-07 | 2018-04-17 | Nucurrent, Inc. | Single structure multi mode antenna for wireless power transmission using magnetic field coupling having an internal switch circuit |
US11205848B2 (en) | 2015-08-07 | 2021-12-21 | Nucurrent, Inc. | Method of providing a single structure multi mode antenna having a unitary body construction for wireless power transmission using magnetic field coupling |
US10063100B2 (en) | 2015-08-07 | 2018-08-28 | Nucurrent, Inc. | Electrical system incorporating a single structure multimode antenna for wireless power transmission using magnetic field coupling |
US9941743B2 (en) | 2015-08-07 | 2018-04-10 | Nucurrent, Inc. | Single structure multi mode antenna having a unitary body construction for wireless power transmission using magnetic field coupling |
US9941590B2 (en) | 2015-08-07 | 2018-04-10 | Nucurrent, Inc. | Single structure multi mode antenna for wireless power transmission using magnetic field coupling having magnetic shielding |
US10985465B2 (en) | 2015-08-19 | 2021-04-20 | Nucurrent, Inc. | Multi-mode wireless antenna configurations |
US10217555B2 (en) * | 2015-12-17 | 2019-02-26 | Rockwell Automation Technologies, Inc. | Compact inductor |
US10283257B2 (en) * | 2016-01-08 | 2019-05-07 | Qualcomm Incorporated | Skewed co-spiral inductor structure |
ITUB20161251A1 (en) * | 2016-03-02 | 2017-09-02 | Irca Spa | Induction hob and method for making induction hobs |
US11460926B2 (en) | 2016-03-31 | 2022-10-04 | Sensel, Inc. | Human-computer interface system |
US10866642B2 (en) * | 2016-03-31 | 2020-12-15 | Sensel Inc. | System and method for detecting and responding to touch inputs with haptic feedback |
US20180062434A1 (en) | 2016-08-26 | 2018-03-01 | Nucurrent, Inc. | Wireless Connector Receiver Module Circuit |
EP3293888B1 (en) | 2016-09-13 | 2020-08-26 | Allegro MicroSystems, LLC | Signal isolator having bidirectional communication between die |
JP6953279B2 (en) | 2016-12-07 | 2021-10-27 | 日東電工株式会社 | Module manufacturing method |
US10424969B2 (en) | 2016-12-09 | 2019-09-24 | Nucurrent, Inc. | Substrate configured to facilitate through-metal energy transfer via near field magnetic coupling |
US11177695B2 (en) | 2017-02-13 | 2021-11-16 | Nucurrent, Inc. | Transmitting base with magnetic shielding and flexible transmitting antenna |
US11283295B2 (en) | 2017-05-26 | 2022-03-22 | Nucurrent, Inc. | Device orientation independent wireless transmission system |
KR20200069803A (en) * | 2018-12-07 | 2020-06-17 | 삼성전기주식회사 | Coil electronic component |
DE102019102576A1 (en) * | 2019-02-01 | 2020-08-06 | RF360 Europe GmbH | RF filter with planar RF coil |
US11271430B2 (en) | 2019-07-19 | 2022-03-08 | Nucurrent, Inc. | Wireless power transfer system with extended wireless charging range |
US11227712B2 (en) | 2019-07-19 | 2022-01-18 | Nucurrent, Inc. | Preemptive thermal mitigation for wireless power systems |
US11115244B2 (en) | 2019-09-17 | 2021-09-07 | Allegro Microsystems, Llc | Signal isolator with three state data transmission |
US11056922B1 (en) | 2020-01-03 | 2021-07-06 | Nucurrent, Inc. | Wireless power transfer system for simultaneous transfer to multiple devices |
US11283303B2 (en) | 2020-07-24 | 2022-03-22 | Nucurrent, Inc. | Area-apportioned wireless power antenna for maximized charging volume |
US11881716B2 (en) | 2020-12-22 | 2024-01-23 | Nucurrent, Inc. | Ruggedized communication for wireless power systems in multi-device environments |
US11876386B2 (en) | 2020-12-22 | 2024-01-16 | Nucurrent, Inc. | Detection of foreign objects in large charging volume applications |
US11695302B2 (en) | 2021-02-01 | 2023-07-04 | Nucurrent, Inc. | Segmented shielding for wide area wireless power transmitter |
US11831174B2 (en) | 2022-03-01 | 2023-11-28 | Nucurrent, Inc. | Cross talk and interference mitigation in dual wireless power transmitter |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2806052A1 (en) * | 1977-02-18 | 1978-10-19 | Tdk Electronics Co Ltd | THERMALLY STABLE AMORPHIC MAGNETIC ALLOY |
JPS5814512A (en) * | 1981-07-17 | 1983-01-27 | Sanyo Electric Co Ltd | Inductor device |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3833872A (en) * | 1972-06-13 | 1974-09-03 | I Marcus | Microminiature monolithic ferroceramic transformer |
US4021705A (en) * | 1975-03-24 | 1977-05-03 | Lichtblau G J | Resonant tag circuits having one or more fusible links |
US4482874A (en) * | 1982-06-04 | 1984-11-13 | Minnesota Mining And Manufacturing Company | Method of constructing an LC network |
US4494100A (en) * | 1982-07-12 | 1985-01-15 | Motorola, Inc. | Planar inductors |
US4613843A (en) * | 1984-10-22 | 1986-09-23 | Ford Motor Company | Planar coil magnetic transducer |
-
1988
- 1988-09-28 US US07/250,401 patent/US4959631A/en not_active Expired - Lifetime
- 1988-09-29 EP EP88309056A patent/EP0310396B1/en not_active Expired - Lifetime
- 1988-09-29 KR KR1019880012666A patent/KR910003292B1/en not_active IP Right Cessation
- 1988-09-29 DE DE3854177T patent/DE3854177T2/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2806052A1 (en) * | 1977-02-18 | 1978-10-19 | Tdk Electronics Co Ltd | THERMALLY STABLE AMORPHIC MAGNETIC ALLOY |
JPS5814512A (en) * | 1981-07-17 | 1983-01-27 | Sanyo Electric Co Ltd | Inductor device |
Non-Patent Citations (3)
Title |
---|
Electrische Machines, Technical University Delft, page 3.47, 07/83 * |
IEEE Trans. Mag., VOL.MAG.15, no.6, 1979, 1803-1805 * |
IEEE Trans. Mag., VOL.MAG.20, no.5, 1984, 1804-1806 * |
Also Published As
Publication number | Publication date |
---|---|
KR890005774A (en) | 1989-05-16 |
DE3854177D1 (en) | 1995-08-24 |
KR910003292B1 (en) | 1991-05-25 |
DE3854177T2 (en) | 1995-12-14 |
US4959631A (en) | 1990-09-25 |
EP0310396A1 (en) | 1989-04-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP0310396B1 (en) | Planar inductor | |
JP2958892B2 (en) | Planar inductor | |
US6175293B1 (en) | Planar inductor | |
US6404317B1 (en) | Planar magnetic element | |
US11404205B2 (en) | Magnetic coupling coil element and method of manufacturing the same | |
JPH04354313A (en) | Flat transformer | |
JPH04363006A (en) | Flat magnetic element | |
JPH05275247A (en) | Thin inductor/transformer | |
JP3540733B2 (en) | Planar magnetic element and semiconductor device using the same | |
Park et al. | Fabrication of high current and low profile micromachined inductor with laminated Ni/Fe core | |
JP3141893B2 (en) | Planar inductor | |
JP2735295B2 (en) | Planar inductor | |
JPS6276509A (en) | Thin type transformer | |
EP0026871B1 (en) | Core for electromagnetic induction device | |
JP2958893B2 (en) | Planar inductor | |
JP3373350B2 (en) | Magnetic components and methods of manufacturing | |
JP3177893B2 (en) | Surface mount electronic components | |
CN113140385A (en) | Laminated core | |
JPH0653044A (en) | Thin inductor or thin transformer and their manufacture | |
JP2993998B2 (en) | Planar inductor | |
JPH04133408A (en) | Plane-surface transformer | |
JPH03276604A (en) | Plane inductor | |
JPH01157507A (en) | Plane inductor | |
JPH03280409A (en) | Flat transformer | |
JPH01157508A (en) | Plane inductor |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 19881011 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB |
|
17Q | First examination report despatched |
Effective date: 19920219 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): DE FR GB |
|
REF | Corresponds to: |
Ref document number: 3854177 Country of ref document: DE Date of ref document: 19950824 |
|
ET | Fr: translation filed | ||
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed | ||
REG | Reference to a national code |
Ref country code: GB Ref legal event code: 746 Effective date: 19980915 |
|
REG | Reference to a national code |
Ref country code: FR Ref legal event code: D6 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: IF02 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: DE Payment date: 20070927 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20070926 Year of fee payment: 20 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20070914 Year of fee payment: 20 |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: PE20 Expiry date: 20080928 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: GB Free format text: LAPSE BECAUSE OF EXPIRATION OF PROTECTION Effective date: 20080928 |